Key Takeaways
- A Zero-Day is a software bug known to hackers but NOT the vendor.
- Developers have "zero days" to fix it before it is exploited.
- They are sold on the black market for millions of dollars.
- Keeping software updated is your only real defense.
Imagine a burglar finding a secret tunnel into a bank that no one else knows about. Not even the architect. That is a Zero-Day.
Defining the Terms
- Vulnerability: The flaw in the code (the hole).
- Exploit: The code written to take advantage of the hole.
- Zero-Day: The state where the exploit is active but no patch exists yet.
Who uses them?
State-sponsored hackers (like the NSA or foreign intelligence) hoard them to spy on targets. Cybercriminals use them to deploy ransomware. The "Stuxnet" virus, which destroyed Iranian nuclear centrifuges, famously used four different zero-days at once.
How much are they worth?
A working zero-day for iPhone (allowing remote takeover without the user clicking anything) can sell for over $2,000,000 on the grey market.
Frequently Asked Questions (FAQ)
Can an antivirus stop a Zero-Day?
Usually, no. Antivirus looks for known signatures. Since a zero-day is unknown, it often flies right past traditional security. Behavioral analysis (AI) has a better chance of spotting it.
How do I protect myself?
Update everything. The moment a vendor (like Apple or Microsoft) releases a security patch, install it. It often fixes zero-days that were just discovered.
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